Device and method for controlling cooking areas with glass-ceramic cooking surfaces

Abstract

The device for controlling a cooking area on a glass-ceramic cooking surface includes an inductive cooking utensil detection device for detecting a cooking utensil on the cooking area and a temperature measurement device for measuring a temperature of the cooking surface. The cooking utensil detection device includes an outer conductor track ( 1 ) and an inner conductor track ( 3 ) nested within said outer conductor track. The temperature measurement device also includes the same outer conductor track ( 1 ) and the inner conductor track ( 3 ), so that the total number of device components is minimized. The outer conductor track ( 1 ) includes, or is supplemented by, a conductor track section ( 2 ) extending from it into a center part of the cooking area ( 4 ). The cooking utensil detection device and the temperature measurement device can operate utilizing the same outer and inner conductor tracks by time-lagged interrogation or with detection signals at different frequencies.

We claim:  
     
       1. A device for controlling a cooking area ( 4 ) on a glass-ceramic cooking surface, said device comprising at least one inductive cooking utensil detection device for detecting the presence of a cooking utensil placed on the cooking area and at least one temperature measurement device for measuring a temperature of the glass-ceramic cooking surface in the cooking area; 
       wherein said at least one inductive cooking utensil detection device includes an outer conductor track ( 1 ) and an inner conductor track ( 3 ), said inner conductor track ( 3 ) being nested within said outer conductor track, and said outer conductor track ( 1 ) and said inner conductor track ( 3 ) are arranged in the glass-ceramic cooking surface within the cooking area; and  
       wherein said at least one temperature measurement device comprises said outer conductor track ( 1 ) and said inner conductor track ( 3 ) of said at least one inductive cooking utensil device, and said outer conductor track ( 1 ) includes a conductor track section ( 2 ) extending from said outer conductor track ( 1 ) into a center part of said cooking area ( 4 ),  
       whereby said at least one inductive cooking utensil detection device and said at least one temperature measurement device share said inner conductor ( 3 ) and said outer conductor track ( 1 ) so as to minimize a total number of device components.  
     
     
       2. The device as defined in  claim 1 , wherein said conductor track section ( 2 ) is an electrode loop having a loop end portion in said center part of said cooking area. 
     
     
       3. The device as defined in  claim 1 , wherein said conductor track section ( 2 ) is an open-ended electrode strip. 
     
     
       4. The device as defined in  claim 1 , wherein said inner conductor ( 3 ) and said outer conductor track ( 1 ) each have a respective circular section, said conductor track section ( 2 ) of said outer conductor track extends from said circular section of said outer conductor track ( 1  ) into said center part and a portion of the inner conductor track is guided around said conductor track section ( 2 ) of the outer conductor track. 
     
     
       5. A method of controlling a cooking area with a glass-ceramic cooking surface, said method comprising: 
       a) providing a device comprising at least one inductive cooking utensil detection device for detecting the presence of a cooking utensil placed on the cooking area and at least one temperature measurement device for measuring a temperature of the glass-ceramic cooking surface in the cooking area; said at least one inductive cooking utensil detection device including an outer conductor track ( 1 ) and an inner conductor track ( 3 ), said inner conductor track ( 3 ) being nested within said outer conductor track, and said outer conductor track ( 1 ) and said inner conductor track ( 3 ) being arranged in the glass-ceramic cooking surface within the cooking area; and wherein said at least one temperature measurement device comprises said outer conductor track ( 1 ) and said inner conductor track ( 3 ) of said at least one inductive cooking utensil device, and said outer conductor track ( 1 ) includes a conductor track section ( 2 ) extending from said outer conductor track ( 1 ) into a center part of said cooking area ( 4 );  
       b) detecting the presence or absence of a cooking utensil in the cooking area inductively by means of said at least one cooking utensil detection device; and  
       c) measuring the temperature of the glass-ceramic cooking surface by measuring a temperature-dependent resistance of the glass-ceramic cooking surface by means of said at least one temperature measurement device.  
     
     
       6. The method as defined in  claim 5 , further comprising additionally measuring said temperature by evaluating a temperature-dependent conductor track resistance. 
     
     
       7. The method as defined in  claim 5 , wherein said temperature of the glass-ceramic cooking surface is measured in an edge region and in a central region of the glass-ceramic cooking surface. 
     
     
       8. The method as defined in  claim 5 , wherein said at least one inductive cooking utensil detection device and said at least one temperature measurement device generate respective signals for cooking utensil detection and for temperature measurement at correspondingly different frequencies. 
     
     
       9. The method as defined in  claim 5 , further comprising time-lagged interrogation of said at least one inductive cooking utensil detection device and said at least one temperature measurement device for cooking utensil detection and for temperature measurement. 
     
     
       10. The method as defined in  claim 5 , further comprising setting relative sensitivities for temperature measurement in an inner region and an outer region of said cooking area by selection of respective lengths and spacing of said conductors.